vcpkg/ports/fltk/fix-build-executable.patch

diff --git a/CMake/FLTKConfig.cmake.in b/CMake/FLTKConfig.cmake.in
index e2de914..c0bee05 100644
--- a/CMake/FLTKConfig.cmake.in
+++ b/CMake/FLTKConfig.cmake.in
@@ -37,17 +37,100 @@ set (FLTK_USE_FILE ${CMAKE_CURRENT_LIST_DIR}/UseFLTK.cmake)
 
 set (FLTK_INCLUDE_DIR "${FLTK_INCLUDE_DIRS}")
 
-if (CMAKE_CROSSCOMPILING)
-  find_file(FLUID_PATH
+if(CMAKE_CROSSCOMPILING)
+
+  # Find a fluid executable on the build host to be able to build fluid programs
+
+  find_program(FLTK_FLUID_HOST
     NAMES fluid fluid.exe
     PATHS ENV PATH
+    NO_DEFAULT_PATH
     NO_CMAKE_FIND_ROOT_PATH
   )
-  add_executable(fluid IMPORTED)
-  set_target_properties(fluid
-    PROPERTIES IMPORTED_LOCATION ${FLUID_PATH}
-  )
-  set (FLTK_FLUID_EXECUTABLE ${FLUID_PATH})
-else ()
-  set (FLTK_FLUID_EXECUTABLE fluid)
-endif (CMAKE_CROSSCOMPILING)
+
+  if(FLTK_FLUID_HOST)
+
+    if(0) # Experimental: currently not used
+      # Import a special 'fluid' target called 'fluid-host' (fltk::fluid-host)
+      # Note: this is "the same as" the CMake variable FLTK_FLUID_EXECUTABLE
+      add_executable(fluid-host IMPORTED)
+      set_target_properties(fluid-host
+        PROPERTIES IMPORTED_LOCATION ${FLTK_FLUID_HOST}
+      )
+      add_executable(fltk::fluid-host ALIAS fluid-host)
+      set(FLTK_FLUID_EXECUTABLE fltk::fluid-host)
+
+    else()
+
+      set(FLTK_FLUID_EXECUTABLE "${FLTK_FLUID_HOST}")
+
+    endif()
+
+  else() # fluid not found on build host
+
+    message(STATUS "FLTKConfig.cmake (cross-compiling): fluid not found on the build host")
+    # note: this assigns "FLTK_FLUID_HOST-NOTFOUND" and running fluid will fail
+    set(FLTK_FLUID_EXECUTABLE "${FLTK_FLUID_HOST}")
+
+  endif()
+
+else(CMAKE_CROSSCOMPILING)
+
+  if(FLTK_CREATE_COMPATIBILITY_ALIASES)
+
+    function(_fltk_make_alias target from)
+      if(TARGET ${from} AND NOT TARGET ${target})
+        # message(STATUS "FLTKConfig.cmake - create alias: ${target} from ${from}")
+
+        # promote imported target to global visibility (CMake < 3.18 only)
+        if(CMAKE_VERSION VERSION_LESS "3.18")
+          set_target_properties(${from} PROPERTIES IMPORTED_GLOBAL TRUE)
+        endif()
+
+        get_target_property(ttype ${from} TYPE)
+        if(ttype STREQUAL "EXECUTABLE")
+          add_executable(${target} ALIAS ${from})
+        else()
+          add_library(${target} ALIAS ${from})
+        endif()
+      endif()
+    endfunction(_fltk_make_alias target)
+
+    if(NOT TARGET fltk::fltk)
+      message(FATAL "FLTKConfig.cmake: target fltk::fltk does not exist!")
+    endif()
+
+    _fltk_make_alias(fltk fltk::fltk)
+    _fltk_make_alias(fltk-shared fltk::fltk-shared)
+
+    _fltk_make_alias(fluid fltk::fluid)
+    _fltk_make_alias(fluid-cmd fltk::fluid-cmd)
+
+    _fltk_make_alias(fltk-options fltk::options)
+    _fltk_make_alias(fltk-options-cmd fltk::options-cmd)
+
+    foreach(target cairo forms gl images jpeg png z)
+      _fltk_make_alias(fltk_${target} fltk::${target})
+      _fltk_make_alias(fltk_${target}-shared fltk::${target}-shared)
+    endforeach()
+
+  endif() # Create aliases ...
+
+  # set FLTK_FLUID_EXECUTABLE: try to use the fltk::target name if it
+  # exists and fall back to 'fluid-cmd' or 'fluid' if not. This will
+  # eventually call the build host's fluid if found in the users's PATH
+
+  if(TARGET fltk::fluid-cmd)  # Windows only
+    set(FLTK_FLUID_EXECUTABLE fltk::fluid-cmd)
+  elseif(TARGET fltk::fluid)
+    set(FLTK_FLUID_EXECUTABLE fltk::fluid)
+  elseif(WIN32)
+    set(FLTK_FLUID_EXECUTABLE fluid-cmd)
+  else()
+    set(FLTK_FLUID_EXECUTABLE fluid)
+  endif()
+
+endif(CMAKE_CROSSCOMPILING)
+
+# Debug: should be commented out
+# message(STATUS "FLTKConfig.cmake: FLTK_FLUID_EXECUTABLE = '${FLTK_FLUID_EXECUTABLE}'")